iommu/amd: Modify set_dte_entry() to use 256-bit DTE helpers

iommu/amd: Modify set_dte_entry() to use 256-bit DTE helpers

Also, the set_dte_entry() is used to program several DTE fields (e.g.
stage1 table, stage2 table, domain id, and etc.), which is difficult
to keep track with current implementation.

Therefore, separate logic for clearing DTE (i.e. make_clear_dte) and
another function for setting up the GCR3 Table Root Pointer, GIOV, GV,
GLX, and GuestPagingMode into another function set_dte_gcr3_table().

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20241118054937.5203-6-suravee.suthikulpanit@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>